1
Q
properties of chemical synapses
A
- uses neurotransmitters
- slower and less reliable
- specific postsynaptic receptors allows for neurons to have different effects
- allows for habituation
2
Q
action of chemical synapse
A
- action potential reaches synaptic terminal, depolarisation opens Ca2+ channels
- Ca2+ enters cell, triggering exocytosis of vesicles containing neurotransmitters into synaptic cleft
- neurotransmitters diffuse across synaptic cleft, binding to receptors on the postsynaptic neuron
- binding initiates a response
3
Q
receptor potential
A
graded potential propagated at receptor
4
Q
EPSPs
A
- excitatory post synaptic potentials
- cell is depolarised
- neurotransmitter binding typically causes Na+ or Ca2+ channels to open
5
Q
IPSPs
A
- inhibitory post synaptic potentials
- cell is hyperpolarised
- neurotransmitter binding typically triggers K+ or Cl- channels to open
6
Q
choligernic receptors
A
- receptors for acetylcholine (ACh) neurotransmitter
- heart has nicotinic receptors that trigger an inhibitory response, G-protein coupled pathway opens K+ ion channels
- muscles have muscarinic receptors that trigger an excitatory response
7
Q
Inactivation of neurotransmitters in synaptic cleft
A
- some taken into blood by glial cells
- some broken down by enzymes so they can be reabsorbed
8
Q
temporal summation
A
Frequent action potentials in the presynaptic cell cause graded potentials in the postsynaptic cell to overlap
9
Q
spatial summation
A
a single postsynaptic neuron has synapses with many presynaptic neurons along its dendrite, EPSPs can sum together as they propagate
10
Q
habituation
A
- decrease in behavioural response to a repeated stimulation
- presynaptic neuron less likely to release neurotransmitters when excited
- facilitates learning and flexibility
11
Q
electrical synapse
A
- direct contact between presynaptic and postsynaptic neuron via gap junctions (continuous cytoplasm)
- rapid and reliable
- does not allow for habituation
- does not allow for change in signal
